JP2567100B2 - Compact acceleration measurement recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to a small-sized acceleration measurement recording device, and a device suitable for recording a temporal change of a minute acceleration applied to an object and a weightlessness experiment method in which an acceleration environment is improved to a μG level. In order to provide a small acceleration measurement recording device, an acceleration sensor,
An AD converter that digitally converts the signal of the acceleration sensor,
A control element that processes digital signals, a removable external storage device that stores change data of acceleration, and a battery that supplies power to the sensor, and the AD
A converter, the control element, the external storage device, and the small acceleration measurement recording device are mounted on a motion system to be measured, and the small acceleration measurement recording device is driven by the battery, and a space shuttle or This is a method for performing weightlessness experiments using ballistic flight of an aircraft, and is achieved by a weightlessness experiment method in which a weightlessness experiment system is suspended from a space shuttle or an aircraft.

[Background of the Invention]

1. Technical Field of the Invention The present invention relates to a small acceleration measurement recording device, and more particularly to a device suitable for recording a minute change in acceleration applied to an object.

Further, the present invention relates to a weightless experimental apparatus for floating the weightless experimental system from the space shuttle or the aircraft in the weightless experiment by the ballistic (or parabolic) flight of the space shuttle or the aircraft.

2. Description of Related Technology In recent years, attention has been paid to the use of weightless environment for the development of new materials. This is because under physical gravity, it is possible to easily cause physical phenomena that cannot be obtained on the ground, such as convection of a solution or a melt, and precipitation of crystals generated therein. This is because there is an inherent possibility of creating the material. Space is the most ideal place to provide a zero-gravity environment, and the space environment, such as the Space Shuttle, a project of the NASA project, and the First Material Experiment Program (FMPT) in Japan, Experiments are being carried out vigorously. In addition, as a weightlessness experiment that can be performed relatively easily, it is typical to provide a weightlessness field by ballistic flight of an aircraft, and to use weightlessness for a short time from a high tower or by free fall of the experimental system at a deep vertical drag. .

However, even in the above system, the gravity applied to the object is close to zero, but it is not completely zero. Generally, in vertical free fall, 1 × 10 ⁻⁵ to 1 × 10 ⁻³ G, and in space experiments 1 × 10 ^-6 〜 1 × 10 ^-3 G, 1 × 10 ^-4 〜 in aircraft experiments
It is said that a weightlessness of about 1 × 10 ^-2 G can be obtained. Further, in the above system, although the acceleration in the vertical direction with respect to the earth, so-called gravity, is close to zero, there is no guarantee that the acceleration applied in the horizontal direction due to the vibration of the experimental system is zero. Therefore, in such an experimental system, it is important to record the acceleration that changes from moment to moment in order to determine the quality of the experiment. In addition, the opportunity for experiments in a zero-gravity environment is greatly limited in terms of time and cost, and it is required to obtain high-level data with a minimum number of experiments, thus improving the reliability of the obtained experimental results. Above, it is important to collect data on acceleration changes.

Conventionally, to measure acceleration, the size is 80 cm x 80 cm x
It required a measuring and recording device that weighed about 20 kg and was about 40 cm. The device is an amplifier that amplifies the signal of the acceleration sensor, an AD converter that digitally converts the signal of the amplifier,
It was composed of a central processing unit that processes signals, an auxiliary storage device that records changes in acceleration, and a pen recorder.

Although such a conventional large and heavy acceleration measuring device has no problem when measuring the acceleration of a spacecraft (space shuttle) or the entire aircraft, it is a local acceleration in a limited space represented by a material experiment. The use of such a large measuring device is not appropriate when the measurement of 10 is required.

Therefore, in the measurement of acceleration change for weightlessness experiments in material development as described above, the conventional large-sized measuring device as described above cannot be applied to measurement of acceleration change at a specific position of the experimental system, Acceleration data had to be represented by data of acceleration changes in the entire spacecraft or aircraft. However, this limits the quality of the experiment because the acceleration at the specific position at the moment when the specific phenomenon occurs cannot be accurately grasped.

In order to solve this problem, conventional acceleration measurement
In the recording device, for example, the acceleration sensor unit
A method of separating from the recording part and connecting with a cable is also conceivable, but in this case, since system disturbance due to external vibration applied through the cable is unavoidable, reliable data cannot be obtained, and For the measurement speed, it was difficult to record at high speed enough to correspond to the image recording of the phenomenon by a video camera, for example.

On the other hand, C-
The performance of static RAM (Storable RAM that can be written / read at any time: S-RAM) is improved by the MOS process.

That is, as the storage density per element increases, a RAM capable of operating with low power consumption is emerging.
As one of applications that make use of the characteristics of the S-RAM, a method of configuring an external storage medium such as a magnetic tape, a magnetic disk, and a floppy disk with the S-RAM can be considered.

The characteristic of the external storage medium that uses this S-RAM is that it can write and read at high speed, so that when it is applied to a computer system, the access time for programs and data can be greatly shortened compared to the conventional method. is there. Also, since it is a solid-state element, it has no moving parts or parts to be worn away, and has the advantages of long life and high reliability. When it is specifically applied to a computer system, it is often used as a single plate-shaped "RAM card" for easy handling.

In order to detect whether the above RAM card is properly installed in the computer system and is in a state where data can be freely accessed, one or more circuits of electrical contacts for detecting the installation or non-installation are provided. A general method is to provide the RAM card and detect the mounting of the RAM card by electrically searching for the contact. Alternatively, RAM card detection by a so-called photo interrupter, which is a combination of a light emitting element and a light receiving element, is frequently used.

However, in the former case, a dedicated contact for detecting the mounting of the RAM card is required, which may increase the number of connector contacts that are difficult to miniaturize, and as a result may hinder the miniaturization of the system. On the other hand, in the latter method, it is necessary to provide a detection optical path for the photointerrupter, which is also disadvantageous in terms of spatial miniaturization, and, for example, even if the RAM card is apparently installed correctly, the contact part Accidents such as poor mounting of the car could not be detected by using this mechanism.

Therefore, the conventional method is disadvantageous in reducing the size of the system using the RAM card. On the other hand, in terms of reliability, there is a problem in the conventional method, and it is difficult to reliably detect the presence / absence of attachment in a state of arbitrarily reading / writing system data.

[Summary of Invention]

The present invention eliminates the problems of such a conventional acceleration measuring / recording device, and mounts an acceleration acting on an object in the same motion system as the object to measure and record a minute change in acceleration. It is an object of the present invention to provide a small acceleration measurement recording device that enables

A small-sized acceleration measurement recording device according to the present invention includes an acceleration sensor, an AD converter that digitally converts a signal from the acceleration sensor, a control element that processes a digital signal, and a removable external storage device that stores a change in acceleration. It is a small-sized acceleration measurement recording device capable of measuring the acceleration acting on an object by mounting it on the same motion system as the object.

That is, in the present invention, in order to solve the above-mentioned problems, data can be easily read by a measuring device (circuit) in place of recording by a pen-type recorder in a conventional acceleration recording device or an auxiliary storage device such as a floppy disk or a magnetic tape. It is possible to record the measured acceleration data at high speed and for a long time by accumulating it in a storage device using a removable solid element and exchanging it according to the amount of measured data. .

Another object of the present invention relates to a storage medium detection method for confirming the mounting of the storage medium when the computer system is mounted with an external storage medium using a semiconductor storage element, and a special device is used to confirm the mounting. It is to do it easily and surely.

In order to solve the above problems, the present invention provides a method of writing and reading arbitrary data with respect to a part or all of the contents of a storage element when an external storage medium using a semiconductor storage element is attached to a computer system for processing. There is provided a storage medium detection method characterized by confirming attachment of the external storage medium by comparing data.

That is, in the present invention, the arbitrary writing / reading function of the RAM card is applied to write arbitrary data at a specific address, which is read out later and collated with the written data. The method of determining that the device is attached is adopted.

Another object of the present invention is to provide an improved method for performing weightlessness experiments.

In order to achieve this object, the present invention proposes a method of performing weightlessness experiments using a space shuttle or ballistic flight of an aircraft, in which a weightlessness experiment system is suspended from the space shuttle or aircraft.

〔Example〕

FIG. 1 shows a typical example of a conventional acceleration measuring device.
The device shown in FIG. 1 has an acceleration sensor 1, an AD converter 2, a control element 3, an input / output circuit 4, an external storage device 5, a pen-type recorder 6 and a power supply circuit 7. This type of device required a size of 80 cm × 80 cm × 40 cm and a weight of about 20 kg.

Although such a conventional large and heavy acceleration measuring device has no problem when measuring the acceleration of a spacecraft (such as a space shuttle) or the entire aircraft, it does not have a problem in a local space within a limited space, such as a material experiment. The use of such large measuring devices is not suitable when acceleration measurements are required.

FIG. 2 is an explanatory view of the principle of the present invention. In the figure, 11 is an acceleration sensor, 12 is an AD converter, 13 is a control element or central processing unit (for example, 8-bit microprocessor), 14 is a removable high-speed external storage device, 15 is a power supply circuit, and 16 is an input / output circuit. Indicates.

If a high-capacity static or dynamic type write / read type storage element (RAM) is used as the high-speed external storage device 14, data can be backed up with a small battery, and an apparent nonvolatile storage device can be realized. In particular, a recording medium that does not have a removable mechanical drive (for example, a static backup with a lithium battery)
It is preferable to use a RAM card) as the external storage device.

In the present invention, as shown in FIG. 2, a light-weight, high-speed removable storage device is provided in the acceleration measurement recording device to enable high-speed measurement of an acceleration value that slightly changes with time. The measurement speed is a sampling time of one frame or less of a video image, and can correspond to image recording data in the measurement system.

Therefore, when it is necessary to proceed with an experiment such as observation of a physical phenomenon that changes at high speed in a limited space such as an aircraft or a spaceship, data that cannot be measured by the conventional device can be obtained.

FIG. 3 is a block diagram of an embodiment of the present invention, showing a compact static acceleration measurement recording device. In the figure, the same components as those shown in FIG. 2 are represented by the same signals. 11a-11c
Is a servo type acceleration sensor (JA5V made by Japan Aviation Electronics Co., Ltd.) which is advantageous for miniaturization and high accuracy, 12 is an AD converter (AD7582 made by Analog Devices Co., Ltd.), and 13 is a central processing unit (Fujitsu Ltd. ), MB68B09), 15 is a power supply circuit (nickel-cadmium battery and constant voltage device), 16 is an LED display and a control switch. 14 is 256kbit static RAM, 4
It is an external auxiliary recording block configured by using one piece, which can be easily attached to and detached from the main body via the multipolar connector 19. Since simultaneous measurement in three-dimensional directions is important in measuring acceleration, for example, three acceleration sensors 11a to 11c are used and set in directions orthogonal to each other, and these outputs are synchronized with the sampling signal 17a. ~ 17c sample −
After being stored in the hold circuit, it is sequentially converted into a digital value by the AD converter. In order to expand the dynamic range of measurement, variable gain control amplifiers 18a to 18c are inserted between the acceleration sensors 11a to 11c and the sample hold circuits 17a to 17c. The central processing element 13 advances all the measurement procedures according to a program written in a ROM (Read Only Memoty). In this case, the data sampling interval is the value input from the switch, and the measurement start and end are also performed by the external switch. Alternatively, the starting point and the ending point of the acceleration measurement can be automatically determined by using the output signal of the acceleration sensor, for example, the one changed by the trajectory of the aircraft or the parabolic flight as a trigger. When performing ballistic flight,
With reference to the acceleration in the Z-axis direction as shown in FIGS. 4 and 5, a point at which the acceleration falls below a predetermined value from large to small is used as a starting point, and a point at which the acceleration exceeds a predetermined value from small to large. It can be automatically sampled as an end point. The control circuit always measures the gravity state of the aircraft, determines the timing of the start of the weightless experiment of the experimental equipment or the start and end samples of free floating, and feeds back that value to the floating mechanism to control the sampling time be able to. The gain control of the variable gain control circuits 18a to 18c is automatically calculated by the central processing element from the value of the measured data with respect to the full scale value.

The shape of the main body is, for example, a rectangular parallelepiped of 12 cm × 18 cm × 12 cm,
The weight is about 1 kg.

The data recorded in the external auxiliary storage device of the small-sized acceleration measurement recording device according to the present invention can be read and processed by another device after the experiment is completed.

An example of the measurement data according to this embodiment is shown in FIGS. 4 and 5.

FIGS. 4 and 5 are examples of acceleration data in the microgravity experiment by the ballistic flight experimental aircraft KC-135 owned by the National Aeronautics and Space Administration (NASA).

Fig. 4 shows the acceleration data collected by fixing the experimental device to the KC-135 fuselage. In this figure, the first half 20
Acceleration of about 2 G (twice the gravitational acceleration) was recorded in the Z-axis (vertical) direction during the second due to the acceleration increase. next
For 20 seconds, microgravity is realized due to the reduction of engine thrust. However, the vibration caused by the fluctuation of the engine and the air flow is about ± 70 mG, which means that the vibration component of the airframe in the microgravity environment cannot be ignored.

That is, FIG. 4 shows a typical acceleration change pattern when the experimental apparatus is fixed to the floor of the aircraft. At the beginning of ballistic flight, high gravity of about 1.8 G is observed in the Z-axis direction, but due to the decrease in engine thrust, it reaches a microgravity state of 0.1 G or less in about 3 seconds. In the Y-axis direction, an acceleration of about 0.2 G is applied at the beginning of ballistic flight, and it is considered that the attitude and thrust of the airframe are reflected. At the end of ballistic flight, high gravity due to the rebuilt aircraft is also added.

FIG. 5 shows data measured by suspending the entire measuring device including the small-sized acceleration measuring recording device according to the present invention from the machine body. In the initial 10 seconds, hypergravity is recorded as in Fig. 4. The next 10 seconds is the time during which the entire experimental device is suspended by hand, and the vibration caused by touching the device is recorded. In the above description, the entire experimental apparatus is, for example, a crystal growth experimental apparatus, or in particular a protein crystal or III-V such as InP or GaAs.
Group synthetic semiconductor crystal or Si or Ge or eg US
P4755363 or Fujitsu Scientific & Technical Journa
l 1988, Vol 24, No. 2, p 126-131. Also, the liquid treatment relating to the experimental equipment for producing protein crystals in the universe or the free surface pattern of liquid droplets or basic data of critical G level affecting the stability of, for example, an aqueous solution droplet, or the elemental technology of the experimental equipment for the fusion of two aqueous solution droplets Regarding the method. However, for the next 5 seconds, the entire apparatus is in a low weight state, the entire apparatus is in a floating state, and the recorded acceleration is almost 0, which means that a very high quality microgravity environment is realized. Have proved.

Note that FIG. 6A is a drawing showing the X, Y, and Z axes in the ballistic flight experiment of FIGS. 4 and 5.

The gravity-free experimental aircraft KC-135 shown in FIG. 6A was originally an aerial refueling machine, and was an early jet passenger aircraft Boeing B-70.
It is a high-performance aircraft that became the prototype of Type 7. NASA is modifying this type of aircraft and operating it for various weightless experiments.

A single ballistic flight pattern is shown in Figure 6B. The experiment was carried out 4 times a day with 10 ballistic flights as one set, and this was repeated for 3 days, for a total of 120 times. Since one microgravity duration is about 20 seconds, 20 seconds x 120 = 2
400 seconds = 40 minutes weightlessness experiment is offered.

This system is mounted on the observation experiment module,
A microgravity experiment was conducted over the US Gulf of Mexico.

From these data, it is obvious that the small acceleration measurement recording apparatus according to the present invention is useful for checking the acceleration data when a high quality microgravity environment is obtained.

7A to 7J are flowcharts for explaining the operation of the apparatus shown in FIG.

FIG. 7A shows the main routine of the software of the apparatus shown in FIG.
Start measurement starting from START shown in 22 and INT in block 23
Measurement routine indicated by ER, file clear routine starting from CLEAR shown in block 24, file No. increment routine shown in block 25, file No. decrement routine shown in block 26, LED drive shown in block 27, and switch shown in block 28 It consists of an input routine.

FIG. 7B shows the measurement routine, F in block 22a.
When an AT (file allocation table) is searched and an empty file exists, CPU interrupt permission is given to the block 22b, data is written in the memory cassette of the block 22c, and the measurement routine is entered.

FIG. 7C shows an interval time changing routine, and it is determined in blocks 23a and 23b whether to increase or decrease the measurement interval time.

FIG. 7D shows a file clearing routine in which the head FAT is searched in block 24b and the FAT is cleared in block 24c when the file is not empty in block 24a. DIR is a directory.

7E and 7F are the file number increment and decrement routines, and FIG. 7G is the system initialization routine.

FIG. 7H shows an LED drive routine for displaying digit data on the LED display.

 FIG. 7I shows a switch input routine.

FIG. 7J shows an interrupt routine, and this routine is activated by an interrupt signal to operate the sample hold circuit, and the held data is converted into digital data and stored in the data buffer.

In the present invention, a memory medium using a semiconductor memory device is used as an external storage medium in a computer system, and whether or not it is completely mounted is confirmed by partial writing and reading of a part of the external memory.

FIG. 8 is an explanatory view of the principle of the present invention. In the figure, assuming that the addresses assigned to the RAM card are N to N + V (N is a start address, V is the total capacity), the addresses P ₁ , P ₂ , ・
.., P _n is selected, and after writing arbitrary data to this address, it is immediately read and the check to compare with the written data is repeated. If this check is performed multiple times and the same data as the written data can be read for all addresses, it is confirmed that the RAM card is properly installed.

In the present invention, other than the electrical contacts that are essentially necessary for a RAM card, that is, the contacts for connecting wirings such as power supply lines, address lines, data lines, and write / read control lines, no physical or hardware Is not required.

Therefore, the space conventionally required is saved for this reason, which greatly contributes to the reduction in size and weight of the system. Further, since writing and reading are also performed for a plurality of addresses, it is possible to serve also as a check as to whether the contacts are reliably connected or whether the S-RAM in the RAM card is functioning normally.

FIG. 9 shows an embodiment in which the recording medium detection system according to the present invention is applied to a 128 kByte RAM card.

Address & H00001, & H out of 128kByte memory space
000C0, & H00F38, & H06566, & H19A1B (& H is a symbol representing a hexadecimal number) was selected. First, the data stored at the above address is temporarily saved. Then, data & H12, & H24, & H58, & H7C, & HD at each of these addresses
Write 3 and read immediately. If all of the read data matches the written data, it is considered that the RAM card is properly installed. If there is no match, RA
M card is considered not installed. If they do not match partially, there is a possibility that the RAM card is defective or the contact in the connector is defective. In that case, perform appropriate processing (such as displaying a message).

FIG. 10 is a more detailed block diagram of the apparatus of the present invention shown in FIG. 3, in which corresponding parts in FIG. 3 are designated by the same symbols as in FIG. No. 11A
Figures 11 to 11H show detailed examples of block diagrams of the apparatus of Figure 10.

FIG. 11A shows the control unit shown in FIG. 10, and the portions shown in FIG. 11A are CPU40, ROM41, RAM42, PTM (program timer) 4
3. Includes PIA (Peripheral Interface Adapter) 44 and memory cassette interface 45. As shown in 11A Figure, ROM41, RAM42, PIA44 address bus A (A ₀ ~A ₁₅₎
And it is coupled to the CPU through the data bus D (D ₀ ~D _7). Elements 40 to 44 are IC ₁ (MBL68B09) and IC ₂ (MB276, respectively)
4-20), IC ₃ (MB8464A-10LLP), IC ₄ (MB8873H) and
Composed of IC (MB8874H).

FIG. 11B shows the memory cassette interface 45 shown in FIG. 10, which is a CP via the address bus A, the data bus D and the connector.
It is connected between the U and the memory cassette 14.

FIG. 11C shows the switch, the display and the remote controller 16 (corresponding to the I / O circuit 16 in FIG. 3) shown in FIG. 10, and the upper part of FIG. 11C shows a display unit having an LED display, The lower part of FIG. 11C shows the switch and remote control.

Figure 11D shows the digital portion of A / D converter 12 and
10 shows its peripheral circuitry including the PGA interface 46 of FIG. 10, and FIG. 11E shows the analog portion of the A / D converter 12 shown in FIG. A / D converter 12 is composed of IC28 (AD7582KN), PGA interface 46 is IC22, IC25, IC2
6 and formed by IC27.

FIG. 11F shows the variable or programmable gain control amplifier (IC30, AD526BD) 18a to 18c shown in FIG. 3, which is composed of a sample hold circuit (IC31, AD389KD) and an inverter amplifier (IC32, LF356H), and is a programmable gain control amplifier. The outputs of 18a to 18c are supplied to the analog portion of the AD converter IC28.

FIG. 11G shows a power supply circuit, which is composed of power regulators IC36 and IC37 and a DC-DC converter IC38 (AD940).

11H shows the memory cassette circuit 14 shown in FIG. 3, which is connected to the memory cassette interface shown in FIG. 11B through the memory cassette connector 19. The memory cassette circuit 14 is composed of four ICs 35 (MB82256), and the capacity of the memory cassette circuit 14 is 128 Kbytes.

FIG. 12A shows a memory map of one embodiment of the storage device according to the present invention. The data management system in the memory cassette will be described below. In Figure 12A the directory DIRECTORY
Corresponds to file Nos. 01 to 99 in & H00002 to & H0000C7, and if the file No. is F, then [F × 2]
The head address of FAT is stored in the address, and the sampling time is stored in the address [F × 2 + 1]. & H00 is written in [F × 2] for the file No. in which no data is stored.

The FAT is placed in & H00102 to & H001FF, and the lower 2 digits of the hexadecimal address correspond to the block number & H02 to & HFF). FA
When T is & H00, no data is recorded in the corresponding block. If the data is recorded,
The FAT number is written. && H01 means that the block is the last block.

Data area is 512 bytes each, block number & H02
~ & HFF. In one block, data is stored in the order of x, y, z according to time series.
Since 2 bytes are required for each axis, 2 × 3 = 6 bytes form one sampling data. Therefore, 512 ÷ 6≈85 (85 + 2) pieces of data are recorded per block. The remaining 2 bytes are unused. The correspondence between the block number and the real address is AD = B × 512, where B is the block number and AD is the real address. this is,
The upper 8 bits of the real address may be regarded as the block number.

The structure of one data is shown in FIG. 12B.
The voltage signal can be converted by data / 2048 × magnification.

FIG. 13 shows a layout of the acceleration measuring system according to the present invention, and symbol 14 shows the memory cassette shown in FIG.

FIG. 14 is a block diagram of the memory cassette reading device in the ground work portion. As shown in the block diagram of FIG. 14, the contents of the memory cassette 14 are transferred to the personal computer 51 via the memory cassette interface 50. The transferred data is the floppy disk drive 52
Stored on a floppy disk. At this point, the data is converted into data that is easy to handle and can be used in other systems.

FIG. 15 is a detailed circuit diagram of the memory cassette interface 50 shown in FIG. In FIG. 15, LS273 and LS175 are latches for specifying the write and read addresses of the memory cassette, LS640 and LS245 are data bus transceivers, and control the data direction at the interface between the personal computer and the cassette memory data. . Further, LS123 is a one-shot multi that controls the timing of writing and reading, or LS20, 30, 139 is an address decoder for selecting the address of the personal computer.

As described above, since the present invention is small and can measure the acceleration applied to an object at high speed, it is easy to change the acceleration of an experimental system set in a minute space that cannot be measured by a conventional device. Can be measured. According to the present invention, high-speed measurement and recording of, for example, 1/30 second or less are possible.

Furthermore, according to the present invention, the RA can be reliably and simply configured.
It is possible to detect the presence or absence of an M card. According to the present invention, a RAM card as an external storage element of a computer is reduced in size and weight, which is useful for reducing the size of the entire system. Moreover, since the presence of the RAM card can be detected with certainty, it is possible to achieve high reliability of the system.

The following shows the results of verification of the performance by using this device in a microgravity experiment using the NASA-dedicated aircraft for weightless experiment KC-135.

FIG. 16 shows a histogram in which the time when the Z-direction acceleration is 0.1 G or less is obtained for each ballistic flight and the time is plotted on the horizontal axis. From now on, focusing on 21 seconds, minimum 18 seconds to maximum 24
The duration is distributed over about a second.

Figure 17 shows that by discarding the data for 1 second before and after the time when the Z-direction acceleration became 0.1 G or less and averaging the data, 1
The residual acceleration level during the ballistic flight was determined. A histogram showing the residual acceleration on the horizontal axis is shown. From this figure, the residual acceleration level shows a distribution with a peak at 12 to 14 mG.

Fig. 18 shows a histogram of 1163 data obtained during the period when the residual acceleration was 5 mG or less (existing 16 times) because the duration was short while the experimental module was floating (Fig. 18
Figure) shows the distribution of residual acceleration. It is shown that the fluctuation is about 1 mG with a standard deviation of about OG (simple average is -2 μG). That is, the floating of the experimental module significantly improves the acceleration environment to the μG level. FIG. 19 shows a similar histogram for 52086 data when the experimental module is fixed to the airframe (described above).

As shown in the previous section, the distribution of residual acceleration of 1163 data obtained during the period when the residual acceleration continued to be 5 mG or less showed a standard deviation of 1 mG around OG (simple average -2 μG). It was found to be a fluctuation.
In other words, the floating environment significantly improved the acceleration environment to the μG level, which is further clarified by comparison with the residual acceleration data (52086 pieces) when fixed to an aircraft (black square).

As shown in FIG. 4, a slight vibration component is superimposed on the acceleration measurement data. In order to investigate the presence or absence of a specific frequency component in the vibration component, we analyzed the vibration in the microgravity state by Fourier transform. An example (Fig. 20) is shown. No vibration component of a specific frequency was found from this analysis. In addition, there is a difference of one digit or more in the power of the vibration component between when it is fixed to the airframe and when the experimental module is suspended. It is mounted on the aircraft KC-135 and compact to measure acceleration during microgravity experiments. A new 3-axis acceleration measurement system was developed. This acceleration measuring system has the following features: 1) Wide dynamic range 2)
It is small and lightweight, 3) the storage medium has high reliability against mechanical shock and vibration, and 4) the battery drive system consumes less power. In microgravity experiments using an aircraft, the distribution of residual gravity in a zero gravity state is almost normal. The average value of residual gravity was 13 ± 25 mG. The period and interval of microgravity were 21 and 81 seconds, respectively. KC-135 The floating residual gravity of the equipment for the reduced gravity experiment with the accelerometer in the room was 0.002 ± 1 mG
And greatly improved.

It is expected that the conventional acceleration measuring device is difficult to be miniaturized because it uses a magnetic tape or a floppy disk as a recording medium, and is vulnerable to being exposed to a severe vibration environment. In addition, there is a concern that vibration generated by the mechanical drive unit may deteriorate the micro-weight environment of the experimental system.
Furthermore, in order to share the acceleration measuring device in a plurality of experiments and measure each local environment, it is desirable to be portable, and it is necessary to incorporate a power supply. On the other hand, measuring not only the microgravity state but also the transient hypergravity state (such as the launch of a rocket) is significant in the execution of the space experiment, and a wide measurement range was required. The following items were issues to solve these problems. (1) Small size
Weight reduction (volume 4000 cc, weight 4 kg or less) (2) Elimination of mechanical drive unit (3) Power source drive possible (4) Wide range (10 G to 10 μG) The above-mentioned problems are achieved by the device of the present invention described above. [Small and lightweight] The memory cassette uses a "memory cassette" that is a modularized 256K-bit static RAM.
It can be easily attached to and detached from the main body by the connector. The signal from the acceleration sensor is digitized by the A / D converter and stored in the memory cassette as time series data. By using a memory cassette, the volume and weight of the recording unit can be reduced to less than 1/5 of the conventional volume, and the mechanical drive unit can be eliminated.

After the experiment, the data recorded in the memory cassette is read by a computer through an interface circuit and subjected to data processing such as various numerical operations for graphing.

[Battery drive]

Power supplies of + 5V are required for digital ICs such as microprocessors and peripheral logic, and ± 15V for analog signal processing elements such as acceleration sensors and high-precision A / D converters. Make + 5V with stabilized power supply from nickel-cadmium battery module (7.2V.1200mAh), DC-DC
Get ± 15V with converter. In an analog signal processing system, noise such as ripple has a large effect, so a low noise DC-DC converter was selected. As a result, one battery module (130 x 45 x 22 mm) enabled continuous operation for 1 hour.

[Wide range]

A variable gain amplifier is installed between the A / D converters of the acceleration sensor, and the microcomputer always controls in real time so that the optimum amplification factor is obtained. The resolution of the A / D converter is 12 bits, which made it possible to achieve a range of 16 bits or more.

This device was used in a microgravity experiment using the NASA's KC-135, an aircraft for exclusive use in weightlessness experiments, and the performance was verified and good results were obtained. We have developed the world's smallest triaxial acceleration measurement recorder suitable for microgravity experiments. Two types of products for aircraft and space have been commercialized. Table 1 shows the performance of these two types.

For microgravity experiments, the acceleration measuring and recording apparatus of the present invention, which is smaller and more portable than ever before, enables precise measurement of the acceleration environment of the experimental apparatus under microgravity.

As an acceleration sensor block, the acceleration sensor for this system is required to be able to detect static acceleration changes, have sufficient accuracy in the microgravity region, be small and lightweight, and have low power consumption. This system uses a servo-type acceleration sensor that is most suitable for this condition, and has a span of ± 1G in the main wing direction (X axis) and advancing direction (Y axis) of the aircraft.
Acceleration sensor with a span of ± 4 G in the vertical direction (Z axis). The measurement control unit amplifies the signal from the sensor by an appropriate magnification, converts it into a digital value by the A / D converter, and then transfers it to the memory cassette. In order to perform this processing, a dedicated microcomputer module using an 8-bit microprocessor is used, and the microprocessor performs the following operations according to the program stored in the ROM.

Optimization of sensor signal amplification Sampling signal generation Memory cassette management Command input / operation status display The memory cassette is a storage medium that uses semiconductor memory. The number of products developed this time is 12 per cassette.
It has a capacity of 8 kbytes and is capable of continuous measurement between 210 and 2100 s corresponding to the sampling interval of 10 ms to 100 ms. Further, in the aircraft experiment, one experiment is completed in a relatively short time, so that the measurement data can be assigned to a plurality of free length files so that the memory capacity can be effectively utilized.

The small acceleration measurement recording device according to the present invention can be used for acceleration measurement recording of a car, a vehicle, or a rocket.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional acceleration measurement recording device, and FIG.
FIG. 3 is an explanatory view of the principle of construction of an acceleration measuring and recording apparatus according to the present invention, FIG. 3 is a block diagram of one embodiment of the apparatus according to the present invention, and FIGS. 4 and 5 are ballistics according to the present invention. Acceleration data obtained from microgravity experiments using a flying aircraft 1
For example, FIG. 6A is a diagram showing measurement axes in acceleration measurement in the parabolic flight aircraft KC-135, and FIG. 6B is KC-135.
FIG. 7A to FIG. 7J are flow charts for explaining the operation of the device of FIG. 3, and FIG. 8 is a diagram showing the trajectory of the ballistic flight of the aircraft. FIG. 9 is an explanatory view of the principle for confirmation, FIG. 9 is a diagram of one embodiment for confirming the correct mounting of the external memory shown in FIG. 8, and FIG. 10 is a more detailed block diagram of the apparatus shown in FIG. 11A to 11H are detailed circuit diagrams in each block of the apparatus of FIG. 10, FIG. 12A is a memory map of the memory cassette shown in FIG. 10, and FIG. 12B is one block of the map shown in FIG. 12A. FIG. 13 is a diagram showing the configuration, FIG. 13 is an external view of an accelerometer according to the present invention, and FIG. 14 is a block diagram of a device for reading the contents of a memory cassette at a work place on the ground after the measurement is completed.
FIG. 15 is a detailed circuit diagram of the cassette interface of the block diagram shown in FIG. 14, FIG. 16 is a diagram showing the distribution of the reduced gravity time, FIG. 17 is a diagram showing the distribution of the average reduced gravity, and FIG. 18 is an experiment. Fig. 19 is a diagram showing the distribution of the reduced gravity data when the device is floating, Fig. 19 is a diagram showing the distribution of the reduced gravity data when the experimental device is fixed to the aircraft, and Fig. 20 is a diagram showing the power spectrum of gravity fluctuation. Is. 11,11a, 11b, 11c ... Accelerometer, 12 ... AD converter, 13 ... Control element, 14 ... External storage device, 15 ... Power supply circuit, 16 ... Input / output circuit.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shozo Fujita 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Takaharu Asano 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (72) Inventor Hiroaki Suzuki 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Akio Sugama 1015, Uedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Naomi Kojima 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (56) References JP 61-168596 (JP, A) JP 60-79164 (JP, U)

Claims (12)

(57) [Claims] 1. A compact acceleration measurement recording device for measuring and recording the momentary change data of acceleration mounted on a motion system, the servo type acceleration sensor and a variable gain control amplifier connected to the servo type acceleration sensor. (PGA) and a sample hold circuit (S & S connected to the variable gain control amplifier
H) and A / which is connected to the sample and hold circuit and converts the analog output signal of the acceleration sensor into a digital signal.
D converter, central processing unit (CPU) connected to the A / D converter for processing the digital signal, read-only storage element (ROM) connected to the central processing unit, writable and readable at any time Memory element (RAM), programmable timer (PTM),
A control element having a variable gain control amplifier interface, a peripheral interface adapter (PIA), and a memory cassette interface, and a mechanical drive unit detachably attached to the control element via a connector for storing acceleration change data are not provided. An external storage device, an input / output device connected to the control element, the servo type acceleration sensor, the variable gain control amplifier (PGA), the sample hold circuit (S & H), the A / D converter, the control An element, the external storage device, and a battery that supplies power to the input / output device, and the central processing unit includes the read-only storage element (ROM)
According to the program stored in, the acceleration sensor signal amplification factor is determined, the sampling signal is generated, the external storage device is managed, the command input / operation status is displayed, and the optimum amplification factor of the variable gain control amplifier is constantly controlled. However, the small acceleration measurement recording device is mounted on the motion system to be measured,
The small acceleration measurement recording device is driven by the battery. 2. The apparatus according to claim 1, wherein the sampling time of the A / D converter (12) is one frame time or less of a video image and corresponds to video recording data in a measuring system. 3. The servo type acceleration sensor (11a, 11b, 11c) according to claim 1 or 2, further comprising three servo type acceleration sensors (11a, 11b, 11c) for measuring and recording change data of accelerations in three mutually orthogonal (x, y, z) directions. apparatus. 4. The gain control of the variable gain control amplifier (PGA) (18) is performed by the central processing unit (CPU) (4) of the control element.
The apparatus according to any one of claims 1 to 3, which is automatically performed by automatically calculating a measurement value with respect to a full scale value according to 0). 5. The recorded data in the external storage device (14) is read and processed by another device after the end of the experiment.
4. The device according to any one of -4. 6. The apparatus according to claim 1, further comprising means for automatically determining a start point and an end point of acceleration measurement by using an output signal from the servo type acceleration sensor (11) as a trigger. . 7. The control element (13) determines a sampling time for starting free-floating or starting a zero-gravity experiment of the experimental apparatus, and stopping flow-floating or ending a zero-gravity experiment, and controlling the sampling time. An apparatus according to any of claims 1-5, wherein the value is fed back to a free floating mechanism. 8. Further comprising means for determining the correct mounting of said external storage device (14) in a computer system for data processing, said means comprising means for writing data to a special address and said data. And a means for comparing the write data with the read data, and a means for determining that the external storage device has been correctly attached when the read data matches the write data. Claim 1 consisting of
The device according to any one of 1. 9. A weightlessness experiment is performed using a space shuttle or an aircraft in ballistic flight through a weightlessness experiment system through a microgravity state in a state of free floating from the space shuttle or the aircraft. A method for measuring and recording acceleration by mounting any one of the described devices on the weightless experimental system. 10. The experiment starts when the acceleration changes from high to low and is below a predetermined value, and the experiment is started, and ends when the acceleration changes from low to high and above a predetermined value. The method according to claim 9, wherein a weightlessness experiment is performed using the apparatus according to claim 2, which ends the experiment. 11. The weightlessness test is a protein growth test, II
In the IV group synthetic semiconductor crystal growth experiment and the intrinsic semiconductor crystal growth experiment, the zero-gravity experiment is started with the acceleration changing from high to low and being equal to or less than a predetermined value. The method according to claim 9 or 10, wherein when the value changes from low to high and becomes equal to or larger than a predetermined value, the sampling is ended by the sampling and holding circuit automatically ending. 12. A small acceleration measurement recording device for measuring and recording an acceleration in the range of 10 G to 10 ⁻⁶ G in a microgravity environment, the servo type acceleration sensor detecting an acceleration in the range of 10 G to 10 ⁻⁶ G. An A / D converter for converting an analog output signal of the servo type acceleration sensor into a digital signal, a control element for processing the digital signal, and an acceleration / removal of an acceleration which is detachably attached to the control element via a connector. An external storage device that does not have a mechanical drive unit that stores change data, a servo type acceleration sensor, the A / D converter, the control element, and a battery that supplies power to the external storage device. An acceleration measurement recording device is installed in a spacecraft or a ballistic flying aircraft in a weightless experiment system capable of free floating from the spacecraft or the aircraft, and the external storage device is the small acceleration device. Detachably mounted with the outside connector means of the casing of the constant recording apparatus, the above-mentioned small acceleration measurement recording device compact acceleration measurement recording device characterized in that it is driven by the battery.